我的GitHub：Powerveil · GitHub
我的Gitee：Powercs12 (powercs12) - Gitee.com
皮卡丘每天学Java
最近在学习数据库PostgreSQL，遇到如何实现对数组类型的数据操作，试着自己尝试学习实现。
话不多说，直接撸代码。
建表语句 PostgreSQL DDL
-- auto-generated definition
create table faviroute_book
(
employee_id integer,
books integer[]
);
insert into faviroute_book values (1,ARRAY [1,2,55]);
insert into faviroute_book values (2,ARRAY [1,2,23]);
insert into faviroute_book values (3,ARRAY [1,23,554]);
select *
from faviroute_book;备注：integer
application.yml
spring:
datasource:
url: jdbc:postgresql://localhost:5432/test
driver-class-name: org.postgresql.Driver
username: postgres
password: 123456FavirouteBookMapper.xml需要的配置
<resultMap id="BaseResultMap" type="com.power.mytest.domain.FavirouteBook">
<result property="employeeId" column="employee_id" jdbcType="INTEGER"/>
<!-- <result property="books" column="books" jdbcType="ARRAY" typeHandler="org.apache.ibatis.type.ArrayTypeHandler"/>-->
<!--这里使用resultMap会识别到，注意这里说的是mybatis/>-->
<result property="books" column="books" jdbcType="ARRAY"
typeHandler="com.power.mytest.handler.ArrayTypeHandler"/>
</resultMap>
<insert id="insertFavirouteBook" parameterType="com.power.mytest.domain.FavirouteBook">
INSERT INTO faviroute_book (employee_id, books)
VALUES (#{employeeId}, #{books, jdbcType=ARRAY, typeHandler=com.power.mytest.handler.ArrayTypeHandler})
</insert>以插入和查询单个为例
FavirouteBookMapper.java
@Mapper
public interface FavirouteBookMapper extends BaseMapper<FavirouteBook> {
int insertFavirouteBook(FavirouteBook favirouteBook);
FavirouteBook getOneByIdMy(Integer id);
}插入方法时需要加上jdbcType=ARRAY, typeHandler=org.apache.ibatis.type.ArrayTypeHandler
typeHandler是一个数组类型转换器，
查询方法时，resultMap的数组字段要加上jdbcType=ARRAY, typeHandler=org.apache.ibatis.type.ArrayTypeHandler
这里我使用的是apache的
也可以使用自定义，当然apache更全，下面是一个自定义的数组类型转换器
import org.apache.ibatis.type.BaseTypeHandler;
import org.apache.ibatis.type.JdbcType;
import org.apache.ibatis.type.TypeException;
import java.sql.*;
public class ArrayTypeHandler extends BaseTypeHandler<Object[]> {
private static final String TYPE_NAME_VARCHAR = "varchar";
private static final String TYPE_NAME_INTEGER = "integer";
private static final String TYPE_NAME_BOOLEAN = "boolean";
private static final String TYPE_NAME_NUMERIC = "numeric";
@Override
public void setNonNullParameter(PreparedStatement ps, int i, Object[] parameter, JdbcType jdbcType) throws SQLException {
String typeName = null;
if (parameter instanceof Integer[]) {
typeName = TYPE_NAME_INTEGER;
} else if (parameter instanceof String[]) {
typeName = TYPE_NAME_VARCHAR;
} else if (parameter instanceof Boolean[]) {
typeName = TYPE_NAME_BOOLEAN;
} else if (parameter instanceof Double[]) {
typeName = TYPE_NAME_NUMERIC;
}
if (typeName == null) {
throw new TypeException("ArrayTypeHandler parameter typeName error, your type is " + parameter.getClass().getName());
}
// 这3行是关键的代码，创建Array，然后ps.setArray(i, array)就可以了
Connection conn = ps.getConnection();
Array array = conn.createArrayOf(typeName, parameter);
ps.setArray(i, array);
}
@Override
public Object[] getNullableResult(ResultSet resultSet, String s) throws SQLException {
return getArray(resultSet.getArray(s));
}
@Override
public Object[] getNullableResult(ResultSet resultSet, int i) throws SQLException {
return getArray(resultSet.getArray(i));
}
@Override
public Object[] getNullableResult(CallableStatement callableStatement, int i) throws SQLException {
return getArray(callableStatement.getArray(i));
}
private Object[] getArray(Array array) {
if (array == null) {
return null;
}
try {
return (Object[]) array.getArray();
} catch (Exception e) {
}
return null;
}
}对应的xml
<insert id="insertFavirouteBook" parameterType="com.power.mytest.domain.FavirouteBook">
INSERT INTO faviroute_book (employee_id, books)
VALUES (#{employeeId}, #{books, jdbcType=ARRAY, typeHandler=org.apache.ibatis.type.ArrayTypeHandler})
</insert>
<select id="getOneByIdMy" resultMap="BaseResultMap">
select * from faviroute_book
where employee_id = #{id}
</select>测试类
@RunWith(SpringRunner.class)
@SpringBootTest(classes = {MyTestApplication.class})
public class Test01 {
@Autowired
private FavirouteBookService favirouteBookService;
@Test
public void test02() {
FavirouteBook favirouteBook = new FavirouteBook();
Integer[] arrays = new Integer[] {43,123,321};
favirouteBook.setEmployeeId(100);
favirouteBook.setBooks(arrays);
favirouteBookService.insertFavirouteBook(favirouteBook);
}
@Test
public void test03() {
FavirouteBook oneByIdMy = favirouteBookService.getOneByIdMy(1);
System.out.println(oneByIdMy);
}
}效果
插入
查询
如果要使用MyBatis Plus查询，而且使用内置的方法就不可以了
测试方法
@Test
public void test01() {
System.out.println("Hello World");
System.out.println("==============使用list()方法====================");
List<FavirouteBook> list = favirouteBookService.list();
System.out.println(list);
System.out.println("==============使用getOne()方法====================");
LambdaQueryWrapper<FavirouteBook> queryWrapper = new LambdaQueryWrapper<>();
queryWrapper.eq(FavirouteBook::getEmployeeId, 1);
FavirouteBook favirouteBook = favirouteBookService.getOne(queryWrapper);
System.out.println(favirouteBook);
System.out.println(Arrays.toString(favirouteBook.getBooks()));
}效果
怎么解决呢？
需要在实体类中加入一些配置，必须加入的有
autoResultMap = true
@TableField(value = "books", jdbcType = JdbcType.ARRAY, typeHandler = ArrayTypeHandler.class)
@TableName(value ="faviroute_book", autoResultMap = true)
@Data
public class FavirouteBook implements Serializable {
@TableField(value = "employee_id")
private Integer employeeId;
@TableField(value = "books", jdbcType = JdbcType.ARRAY, typeHandler = ArrayTypeHandler.class)
private Integer[] books;
}为了让框架识别通过实体类加过直接生成的resultMap，框架默认识别不了我们自己写的resultMap
查看效果
